Self-leveling device with clamping means for adjusting initial spring tension



O 7, 1964 l. BRONSON 3,154,029

SELF-LEVELING DEVICE WITH CLAMPING MEANS FOR ADJUSTING INITIAL SPRINGTENsIoN Filed Aug. 24, 1961 3 Sheets-Sheet 1 M N N X N. M"

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SELFLEVELING DEVICE WITH CLAMPING MEANS FOR ADJUSTING INITIAL SPRINGTENSION Filed Aug. 24, 1961 3 Sheets-Sheet 3 flv WQ M United StatesPatent 3,154,029 SELF-LEVELING DEVICE WITH CLAMPING MEANS FUR ADJUSTINGINITIAL SPRING TENSIGN Irving Bronson, Brooklyn, N.Y., assignor, bymesne assignments, to American Machine & Foundry Company, New York,N.Y., a corporation of New Jersey Filed Aug. 24, 1961, Ser. No. 133,7267 Claims. (Cl. 108-136) This invention relates to a self-leveling devicefor receiving storing and dispensing articles.

The subject application is a continuation in part of my copendingapplications Serial Numbers 49,856, 49,857 and 49,912 filed August 16,1960 and Serial Number 65,- 137 filed October 26, 1960, now US. Patents3,123,218, 3,123,829, 3,123,023, and 3,123,024, respectively.

Under many circumstances, it is desirable to dispose a series ofarticles in stacked relation upon a wheel-mounted carrier and to removesaid articles therefrom as desired. Thus, for example, restaurants orsimilar food service institutions may require that a series of dishracks be stacked as they are removed from a dishwashing machine andthereafter transported to another location at which the racks areunloaded as required. In this, as well as in many other applications, itis quite important that the loading and unloading points he maintainedat a constant level regardless of the number of stacked articlesdisposed upon the carrier in order to minimize the amount of effortrequired and to maintain the uppermost rack or article at the mostdesirable level. Although self-leveling devices of this character havebeen suggested, they have been characterized by shortcomings which areovercome by the instant invention.

It is therefore an object of this invention to provide a self-levelingdevice for receiving, storing and dispensing articles which is simple inarrangement and construction and which effectively maintains a pluralityof articles in stacked relation, with the uppermost article beingmaintain at a predetermined level regardless of the number of articlescomprising the stack.

Another object of this invention is to provide a selfleveling device ofthe character indicated which may be readily adjusted to accommodatevarious stacks of articles as when it is desired to change over from astack comprised of articles of a certain weight and vertical dimensionto a stack comprised of articles of a different unit weight and verticaldimension.

It is also an object of this invention to provide a device of thecharacter indicated wherein it is not necessary to employ special typesof spring elements in order to provide for the maintenance of a stack ofarticles at a predetermined constant level regardless of the number ofarticles comprising the stack and variations in the characteristics ofthe group.

An additional object of this invention is to provide an arrangementwherein a stack elevating spring arrange ment is employed which providesfor varying the stress exerted upon the spring means to accord with thedegree of winding or unwinding thereof. It is a further object toprovide generally improved means for adjusting the jacent the corners ofthe base.

initial spring tension and degree of leverage exerted 3,154,029 PatentedOct. 27, 1964 apparent from the description thereof contained in theannexed specification, or will otherwise become obvious. It will beunderstood that the invention here disclosed may be employed for otherpurposes to which the structure and arrangement are adapted.

In the accompanying drawings:

FIGURE 1 is a side elevational view of a self-leveling device embodyingthe features of the instant invention, partly in section and alsoshowing the carrier platform under load in broken lines;

FIGURE 2 is a fragmentary side elevational view of the upper portion ofthe self-leveling device depicted in FIGURE 1;

FIGURE 3 is a fragmentary plan view of the form of the inventiondepicted in FIGURE 1;

FIGURE 4 is a fragmentary side elevational view taken on line 44 ofFIGURE 3, showing one of the carriage assemblies employed in said formof the invention, said carriage assembly being shown partly in sectionand being in operative association with one of the upright frameassemblies provided in said form of the invention;

FIGURE 5 is a cross-sectional view taken about the line 5-5 of FIGURE 1;

FIGURE 6 is a fragmentary side elevational view of one of the carriageassemblies employed in said form of the invention, said view beingsimilar to that depicted in FIG- URE 4 but showing the spring memberemployed in connection with said carriage assembly wound to a positionwherein the spring exerts a substantially greater torque than it doesfrom the position depicted in FIGURE 4;

FIGURE 7 is a cross-sectional view taken about the line 7-7 of FIGURE 5;and

FIGURE 8 is a perspective view of a clamping device utilized in thepresent invention.

A self-leveling, receiving, storing and dispensing device embodying thefeatures of the instant invention is illustrated in FIGURE 1 of theaccompanying drawing. As may be seen from said figure, the devicecomprises a wheel-mounted base assembly, designated generally by thenumeral 10, which supports an upright frame assembly, designatedgenerally by the numeral 11. A carrier assembly, designated generally bythe numeral 12 and disposed forwardly of the upright frame assembly,receives, stores and dispenses the desired articles and is mounted forvertical movement on the upright frame assembly 11. Articles, such asdish rack for example, are stacked upon the carrier platform 12a of thecarrier assembly and with the placement of each successive rack thereon,the stack is depressed or lowered so that the uppermost article in thestack is always at the same working level. Conversely, as each articleis successively removed from the stack, the entire remaining stack iselevated so that the next succeeding article is brought up to thedesired working level.

The base assembly 10 in the form of the invention illustrated comprisesa generally rectangular frame 13 which is advantageously formed of anglemembers of steel, aluminum or other suitable material. The frame isfurther provided with casters 14, which are mounted ad- By forming thebase in the manner indicated, it is possible to make use of this portionof the device for further storage of used racks for example. Thus, as arack is removed from the stack upon the carrier platform the carrier iselevated as a consequence of such removal, a used rack may be disposedupon the frame assembly in the space thus formed.

The upright frame assembly 11 is mounted upon the pin 31.

wheeled base 14) and comprises a pair of vertical trackways 15 and 16,disposed on the opposing sides of the base frame 13. Each of trackways15 and 16 comprises guide rails 17 having flange portions 18 and headportions 19. On each side of the base assembly an inclined brace member20 extends from the base to the upper portion of the guide rails,thereby supporting the said trackways.

Each of the guide rails receives a vertically movable carriage assemblywhich supports an important feature of this invention residing in themeans for presetting a spring drum so as to provide a predeterminedresistance to variation in the level of the carrier platform 12a.

Thus, as may be seen by references to FIGURES l to 5, the upright frameassembly houses a pair of rectangular carriage plates 21 Which mount atransverse hollow drum'22 'therebetween. Each plate 21 mounts a ballbearing 24 which rotatably secures a shaft 25. Intermediate of saidbearings 24 are provided a pair of flanged collars, generally designatedby the numerals 26, 27, the bodies 28 of said collars 26, 27 beingformed with grooves 29 to receive a coiled torsion spring 30. One of thecollars 26 is secured to the drum 22 by a press fit and additionally maybe staked thereto. The other of said collars 27 is rotatable withrespect to the drum. The shaft is rotatable relative to collar 26 butcollar 27 is press fit to shaft 25 and is secured thereto by a The endsof the aforesaid coiled torsion spring are also suitably affixed to thecollars so that any rotation of the collar 26 with respect to the shaft25 imparts aset or corresponding resistance to any opposing rotationwhich may be exerted upon the shaft 25.

Drum 22 is mounted on the fixed housings 24a of ball bearings 24 bymeans of clamps 23. As best shown in FIGURE 8, each clamp 23 has acircular mounting portion 66, separated from the remainder of the clampby a peripheral slot 62 and a clamping portion 64 provided with thecompanion clamping arms 6666. The mounting portion 66 is provided on itsupper inner surface with a projection 68. Each clamp 23 is mounted onits associated bearing housing 24a by means of the mounting portion 60,slot 62 defining cooperating tabs 70-70 which are urged together forthis purpose. The opposite ends of drum 22 are received in the clampingportions 64, the clamping arms 6666 being spread apart to facilitate theinsertion of the drum and then being secured together by a bolt 72passing through the armapertures 74 and retained in position by a nut76.

The rotation of the collar 26 with respect to the shaft 25 may beaccomplished by loosening the nuts 76 on bolts 72 in each clamp 23sufficiently for manual rotation of the drum so as to rotate the collar26 which rotates therewith. After the drum has been rotated to providethe desired stress or torque to spring 30, clamping arms 66 associatedwith collar 26 are clamped together by tightening nut 76, the procedurethen being repeated to clamp arms 66 associated with collar 27.

It will be noted from the foregoing arrangement that the coiled torsionspring 30 may be rotated with respect to the shaft 25 by simplyloosening clamp arms 66 of both clamps 23 and the drum 22 so that itwillbe displaced from an initial position thereof. As a result of suchrotation, it is possible to produce any desired amount of torsion in thespring 36, maintaining the drum in adjusted position by tightening nuts76.

The shaft is provided with a pair of opposing flanged pulleys 37 securedto the ends of the shaft by suitable fastening elements such astransverse pins 38, the pulleys 37 being provided with two pair of outerand inner cover plates 39, 40 secured by suitable bolts 90 to theopposing guide rails 17.

The external periphery of each of the pulleys 37 receives a flexiblemember, such as a flexible band 46, which is secured to said pulley, asby a suitable pin or key 37a engaged with a portion of said band withinan open notch 371; provided in each of the pulleys 37, the key passingthrough diametrical openings 37c provided in the hollow shaft 25. Morespecifically, it Will be noted that the band is refiexed into a U-shapedportion at the free end thereof by means of the pin 37a extendingthrough the shaft openings 370. As a result, the U-shaped band portionis wedged into position in the shaft by the pin but may be readilyreleased from the shaft by withdrawing the pin therefrom. The carriageplates 21 are supported within the vertical trackways 15, 16 and sincesaid plates are affixed to the carrier assembly, as by bolts 47, thesaid carrier assembly is also supported between said trackways.

It will be seen from this arrangement that the coiled spring 30 may beinitially deflected to any desired extent by rotation of the drum 22.Such deflection of the torsion spring 30 together with any correspondingtension of the band 46 will vary the lifting force applied to thecarrier platform to accommodate items of different weights.

The position of each of the bands 46 with respect to the center of eachpulley 37 may be varied by the following described mechanism. Thus, theouter and inner cover plates 39, 41) are provided with arcuateextensions 39a, 40a disposed rearwardly of the upright frame assembly11. A reel 41 is disposed between each pair of cover plates 39, 40, thesaid reel 41 being secured to a shaft 42 extending through the coverplates 39, 40. A generally U-shaped handle 43, including a pair ofsubstantially parallel arms 44 and an intermediate connecting member 45,is disposed between the opposing inner cover plates 40, the said arms 44being secured, as by welding to the shafts 42. Said handle 43 may bemanually engaged to permit movement of the self-leveling device as awhole, as by pushing, for example, and may also be used for winding ofthe band 46 and unwinding thereof from the pulleys 37 in the mannerhereafter described. The aforesaid band 46 is disposed upon the reel 41and secured thereto as by a'pin or key 59 engaged with a portion of saidtape disposed in an open notch 51 provided in said reel 41. The saidtape 46 is wound upon each reel 41 by rotating the handle '43, as, forexample, in the direction indicated by the arrow shown in FIGURE 3,thereby causing said handle to occupy extreme positions. At the sametime, said band is correspondingly unwound from the pulleys 37. Anadjustable guide means 82 is provided for each band 46 between eachpulley 37 and associated reel 41. Said guide comprises a roller 83provided on an adjustable mount 84 which is vertically adjustable bymeans of a screw 85 passing through the tines of a fork 86 providedthereon.

It will be observed that when the handle 43 is not being employed forthe winding of the reel 41, as aforesaid, it may be locked in itsextreme rearward position shown in solid lines in FIGURE 3, by means ofa pair of transverse screws 52, which project through the arcuateextensions 39a, 46a of the outer and inner cover plates 39, 40, the saidarcuate extensions being maintained'in spaced relation with respect toeach other by a collar 53 disposed intermediately of each pair of saidextensions, the said arcuate extensions 40a of the inner cover plates 40also being maintained in spaced relation with respect to offset portions54 of the arms 44 by a collar 55 disposed between said arcuateextensions 40a and said offset portions 54 of the arms 44. The screws 52are threadedly engaged with the handle 43 when it is locked againstrotation, but may be removed to permit the rotation of the handle andwinding of the band 46 upon the reels 41 to any desired extent.

In this way, the moment arm of the band 46 with respect to the axis ofeach of the pulleys 37 may be preset as desired.

With this arrangement, any given weight placed upon the platform of thecarrier assembly will accomplish a corresponding deflection of the bandand of the carriage plate and carrier assembly, as, for example, to theposition depicted in broken lines in FIGURE 1 and designated by thenumerals 12b and 21b, the amount of such deflection being determined bythe moment arm of said band with respect to the axis of the shaft 37 andthe present torsion of the coiled spring 30. In this connection, it willbe particularly noted that the moment arm of the band will shorten asthe carrier platform descends and the counter-pull of the springincreases and the said moment arm will lengthen as the carrier platformrises and the counter-pull of the spring decreases.

It will also be noted that in the upper and lower por tions of thecarriage plate 21 in each trackway, carriage rollers 48 are mounted,each of said rollers being provided with suitable flanged portion forengagement with the trackways. As may be seen in FIGURES 1 and 6, theband contacts the periphery of the pulley at a point which is offsetwith respect to the vertical axis of the carriage plate, thereby cantingthe carriage roller into contact with the head portions 19 of the guiderails 17.

The carriage rollers may be suitably mounted upon the carriage plate bya conventional shaft and nut assembly 49, said mounting permittingrotational move ment of the carriage rollers.

With this arrangement, the carrier platform may receive a plurality ofarticles of equal weights, such as dish racks, the uppermost of saidracks being maintained at a predetermined level. When the stacks arecomposed of a different weight, the level thereof may be adjusted byappropriate setting of the spring drum in conjunction with positioningof the moment arm of the band 46 with respect to the axis of each of thepulleys 37. It will be seen that such adjustment is easily, quickly andconveniently accomplished, and does not require the employment ofspecialized spring elements, the coiled torsion spring Within the springdrum being of conventional design. Moreover, a definite positioning ofthe carrier platform is accomplished without the necessity of using adelicate or unduly complex mechanism.

It will also be observed that the arcuate extensions 39a of the outercover plates 39 are provided with at least one vertical slot 56extending radially of the reel 41 adjacent to each of said arcuateextensions 39a, thereby permitting easy observation of the flexible band46 disposed thereon. The slot 56 is also provided with a series oflinear graduations 57 adjacent to that portion of the band 46 which iswound upon the reel 41, each of said graduations 57 being spaced fromthe adjacent of said graduations at a distance equal to one or morethicknesses of the band 46, thereby permitting determination of thenumber of windings of said band 46 upon the reel 41 when the outermostof said windings is gauged against said linear graduations. In this way,the setting of the reel 41 is easily determined, said setting in turndetermining the moment arm of the band with respect to the axis of thepulley 37.

In order to accomplish the initial setting of band 46 upon reels 41,drum 22 is first released for rotation free of the action of torsionspring 3i). This release of drum 22 for free rotation is accomplished byloosening nuts 76 to allow for the separation of the preferablyresilient clamping arms 66 in each clamp 23. The restraint upon one endof the spring is thus removed and shaft 25 and pulleys 37 are freed fromthe biasing action of the spring and consequently the entire carrierassembly 12 drops to the base under its own Weight. The position of eachof the bands with respect to the center of each of pulleys 37 may thenbe adjusted as desired by means of handle 43 which winds the bands onreels 41. When the lever arm has thus been adjusted to the desiredpoint, clamp arms 66 in each clamp 23 are tightened. This restores theoperative connection between shaft 25 and drum 22 through the torsionspring. By continuing the operation of handle 43, the torsion spring iswound as the bands are additionally reeled up. The carrier assembly thusrises under the increased tension of the spring. With the carrierassembly thus elevated, handle 43 is locked in fixed position in themanner heretofore indicated. The torsion spring may then be adjusted toany desired degree of tension by loosening clamps 23, rotating drum 22and tightening the clamps in the manner heretofore indicated.

The embodiment of the invention illustrated and described hereinabovehas been selected for the purpose of clearly setting forth theprinciples involved. It will be apparent, however, that the presentinvention is susceptible to being modified in respect to details ofconstruction, combination and arrangement of parts which may be resortedto without departure from the spirit and scope of the invention asclaimed.

I claim:

1. In a self-leveling device comprising, a base member, an upright framesupported by said base member, vertically movable carriage meansretained within said frame, a platform supported by said carriage meansfor the receipt of articles thereon, rotatable means associated withsaid upright frame, carriage supporting carrier means disposed upon saidframe, a rotatable shaft housed within said carriage supporting carriermeans, a pulley aflixed to said rotatable shaft, a flexible bandsupporting said carriage, said band communicating be tween saidrotatable means and said pulley, a coiled torsion spring disposed onsaid shaft to bias the latter and drum means in which said shaft ismounted for rotation, that improvement which comprises means includingsaid spring for effecting an operative connection between said shaft andsaid drum means, means mounting said drum means for rotation relative tosaid shaft for imparting an initial deflection to said spring, and meansfor releasably clamping said drum means in a rotatably adjusted positionthereof for retaining said initial deflection of said spring.

2. A self-leveling device as in claim 1, said clamping means comprisinga pair of clamps mounted in laterally spaced relation by said carriagesupporting carrier means, each of said clamps having a releasableclamping portion in which an adjacent end of said drum is clamped.

3. A self-leveling device as in claim 1, said clamping means comprisinga pair of clamps mounted in laterally spaced relation by said carriagesupporting carrier means, each of said clamps having a releasableclamping portion in which an adjacent end of said drum is clamped, saidcarriage supporting carrier means having a pair of laterally spacedrotary bearing means for said shaft, said clamps being mounted by saidbearing means.

4. A self-leveling device as in claim 1, said clamping means comprisinga pair of clamps mounted in laterally spaced relation by said carriagesupporting carrier means, each of said clamps having a releasableclamping portion in which an adjacent end of said drum is clamped, saidcarriage supporting carrier means having a pair of laterally spacedrotary bearing means for said shaft, said clamps being mounted by saidbearing means, said clamps each having a mounting portion separated fromthe clamping portion thereof by a peripheral slot which definescompanion mounting tabs.

5. A self-leveling device as in claim 1, said clamping means comprisinga pair of clamps mounted in laterally spaced relation by said carriagesupporting carrier means, each of said clamps having a releasableclamping portion in which an adjacent end of said drum is clamped, saidcarriage supporting carrier means having a pair of laterally spacedrotary bearing means for said shaft, said clamps being mounted by saidbearing means, said clamps each having a mounting portion separated fromthe clamping portion thereof by a peripheral slot which definescompanion mounting tabs, and said clamping portion having a pair ofcooperating clamping arms in which the adjacent end of the drum isreceived and means to releasably clamp said arms together.

6. A self-leveling device as in claim 1, said operative connectioncomprising a collar to which one end of said spring is secured, saidcollar being secured to said drum, said shaft extending'through saidcollar and being rotatable' relative thereto.

7. A self-leveling device as in claim 1, said operative connectioncomprising a collar to which one end of said spring is secured, saidcollar being secured to said drum, said shaft extending through saidcollarand being rotatable relative thereto, and a second collar to whichthe other end of said spring is secured, said second collar being fixedto said shaft and rotatable relative to said drum.

References Cited in the file of this patent UNITED STATES PATENTSHagerstrom July 29, Blodgett Sept. 1, Rockwood Jan. 18, Kahler Mar. 27,Bockius July 17, Weaver Apr. S, Jensen June 24, Robinson Mar. 10, GibbsDec. 15, Ross Apr. 27,

Simpson June 12,

1. IN A SELF-LEVELING DEVICE COMPRISING, A BASE MEMBER, AN UPRIGHT FRAMESUPPORTED BY SAID BASE MEMBER, VERTICALLY MOVABLE CARRIAGE MEANSRETAINED WITHIN SAID FRAME, A PLATFORM SUPPORTED BY SAID CARRIAGE MEANSFOR THE RECEIPT OF ARTICLES THEREON, ROTATABLE MEANS ASSOCIATED WITHSAID UPRIGHT FRAME, CARRIAGE SUPPORTING CARRIER MEANS DISPOSED UPON SAIDFRAME, A ROTATABLE SHAFT HOUSED WITHIN SAID CARRIAGE SUPPORTING CARRIERMEANS, A PULLEY AFFIXED TO SAID ROTATABLE SHAFT, A FLEXIBLE BANDSUPPORTING SAID CARRIAGE, SAID BAND COMMUNICATING BETWEEN SAID ROTATABLEMEANS AND SAID PULLEY, A COILED TORSION SPRING DISPOSED ON SAID SHAFT TOBIAS THE LATTER AND DRUM MEANS IN WHICH SAID SHAFT IS MOUNTED FORROTATION, THAT IMPROVEMENT WHICH COMPRISES MEANS INCLUDING SAID SPRINGFOR EFFECTING AN OPERATIVE CONNECTION BETWEEN SAID SHAFT AND SAID DRUMMEANS, MEANS MOUNTING SAID DRUM MEANS FOR ROTATION RELATIVE TO SAIDSHAFT FOR IMPARTING AN INITIAL DEFLECTION TO SAID SPRING, AND MEANS FORRELEASABLY CLAMPING SAID DRUM MEANS IN A ROTATABLY ADJUSTED POSITIONTHEREOF FOR RETAINING SAID INITIAL DEFLECTION OF SAID SPRING.